An antifuse is an electrical device that starts with a high resistance and is designed to permanently create an electrically conductive path (typically when the voltage across the antifuse exceeds a certain level). Antifuses can be used to permanently program integrated circuits (ICs). For example, certain programmable logic arrays (PLAs) use antifuses to configure logic circuits and create a customized design from a standard IC design. Antifuse PLAs are one time programmable.
Philipe Candelier et al., “One Time Programmable Drift Antifuse Cell Reliability,” 38th Annual International Reliability Physics Symposium, San Jose, Calif., 2000, describes a configuration in which the gate oxide layer of a complementary metal oxide semiconductor (CMOS) IC is used as the capacitor layer, allowing the fabrication of the antifuse during a standard CMOS process. The antifuse is a standard N+ polysilicon/5 nm oxide thickness/Nwell capacitor. The gate oxide is very well controlled at the process level (thickness, breakdown voltage, lifetime and the like) and can be broken with a limited current compared to poly or metal fuse. A high programming voltage for the antifuse is achieved on the low voltage CMOS process with a standard NMOS transistor in which the drain junction is replaced by Nwell implantation (Drift NMOS).
An antifuse design is desired that is easily scalable for advanced technology nodes.